basket = {'apple', 'orange', 'apple', 'pear', 'orange', 'banana'}
print(basket)                      # 删除重复的
a = 'orange' in basket                 # 检测成员
print(a)
b = 'crabgrass' in basket
print(b)

c = set()
print(c)
aSet = set('abracadabra')
bSet = set('alacazam')
print(aSet)

print(aSet - bSet)
print(aSet | bSet)
print(aSet & bSet)
print(aSet ^ bSet)

set1 = {x for x in 'abracadabra' if x not in 'abc'}
print(set1)